Article Summary:
Nest Protect tests itself to make sure that its batteries, sensors, speaker, horn, and Wi-Fi connection are working. You’ll see the results in the Nest app and during Nightly Promise when you turn off the lights for the night. You don’t need to worry if the batteries are low, if the speaker is working or if Nest Protect has any other problems. You’ll know.
For almost 50 years, people have had to test their smoke alarm by pressing its button. But 9 out of 10 people don't test their smoke alarms as often as they should (source: National Fire Protection Association).
We knew there had to be a better way. Just like you don't need to guess when your car is low on gas, you shouldn't have to wonder if something as important as your smoke or carbon monoxide alarm is working.
Nest Protect tests itself and, thanks to Nightly Promise, it tells you each night if everything is okay so you can go to sleep with peace of mind. You can also check the Nest app at any time to see how your Nest Protects are doing.
Learn more about Nightly Promise >
What Self Test checks
There are some differences between 1st and 2nd generation Nest Protects; only 2nd gen Protects can check their speaker and horn. Nest Protect's Self Test automatically tests the following things:
- Sensors: smoke, carbon monoxide
- Audio: speaker and horn (2nd gen Nest Protect only) Learn more
- Power: battery charge (including backup batteries for wired Nest Protect) and 120V line power connection for wired Nest Protect
- Wi-Fi connection: so you can receive alerts and notifications on your phone.
Note: Wi-Fi connectivity can vary over the course of the day because of wireless interference, service interruptions and other factors. To avoid sending you repetitive notifications when your Internet connection is spotty, Nest Protect will show you it's offline if it hasn't been able to connect to the Internet in the last 48 hours. Nightly Promise will glow yellow, and you'll see the information in the Nest app.
The 2nd generation Nest Protect also runs a Sound Check once a month, to test its speaker and horn - without you having to be at home to run the test.
Learn more about Sound Check >

How to see and hear Self Test results
Your Nest Protect will also let you know Self Test's results during Nightly Promise. If Self Test finds a problem with any of your Nest Protects, such as a low battery, all Nest Protects in your home will let you know during Nightly Promise.
When you turn out the lights, Nest Protect's light will glow green to show you that everything's okay, but it will glow yellow if there's a problem. To hear what's wrong, you can press the Nest button.

What will I see and hear from Nest Protect? >
What do all the lights mean on Nest Protect? >
You can also look in the Nest app. Simply tap the info button (it's the circle with an "i" in the middle) on the Nest Protect you want to check, and you'll see the time and results of the last test.
If there's an issue, you'll also see what happened in Safety History.
Can I turn off Self Test?
Self Test helps ensure that your Nest Protect is working to keep you safe, and gives you essential information when you need it, so it can't be disabled. However, you can disable Nightly Promise at any time in the Nest app. If you do this, your Nest Protect's light ring won't glow when you turn off the lights to let you know if everything is OK or if there's a problem. Here's how:

1. From the Nest app home screen, tap Protect.
2. Tap the Settings icon in the top right corner of the screen.
3. Pick the Nest Protect that you want to control.
4. Select Nest Sense and then Nightly Promise.
5. Set the Nightly Promise switch to off.